How can I loop through UITableView's cells?

I have n sections (known amount) and X rows in each section (unknown amount. Each row has a UITextField. When the user taps the "Done" button I want to iterate through each cell and do some conditional tests with the UITextField. If the tests pass data from each cell is written to a database. If not, then a UIAlert is shown. What is the best way to loop through the rows and if there is a more elegant solution to this please do advise.